I. To assess the effect of metformin on additional relevant biomarkers in tissue via immunostaining. This will include the effects on levels of colorectal mucosa proliferation estimated by: phosphorylated AMPK (pAMPK), phosphorylated AKTserine 473 (pAKT), phosphorylated mTOR, phosphorylated insulin receptor (pIR), phosphorylated IGF-1 (pIGF-1) receptor, and Ki-67.